"...some of his (Sullivan's) finest work is from these last years, especially the banks in small prairie towns. The best of these is the National Farmers' Bank...Though much smaller in scale than the earlier skyscrapers, the bank is just as clearly expressed in its parts. The main banking room is a single cubical space enclosed by a box, indicated by the wide stained-glass lunette windows. The base is of red sandstone, with dark red brick walls. Ornamentation is concentrated in panels, of bronze-green terra cotta, with intricate cast iron escutcheons at the corners; the cornice is simply corbeled brick courses. To the rear is a separate block housing offices and shops, a speculative venture by the bank, but clearly related to the bank in materials and design."

— Leland M. Roth. A Concise History of American Architecture. p183.

"Stand back from the corner of Broadway and Cedar Streets in Owatonna, Minnesota. See how Sullivan's National Farmers' Bank stands on the corner opposite the park. Massive and stately—68 feet broad and about 53 feet tall—its silhouette and ornamental patterns strike golden section rectangles. Great vaulted windows pierce the deep walls, and a row of dark square windows punctures the base. Strength in concept; surprise and contradiction in detail.

"The great ornamented mass anchors the lines of street facades, bringing sequences of jumbled store fronts and one fine, arcaded office building (Sullivan's also) to a monumental climax."

— Yukio Futagawa, ed. and photographs with Albert Bush-Brown, text. Global Architecture: Louis H. Sullivan: National Farmers' Bank, Owatonna, Minnesota Merchants' National Bank, Grinnell, Iowa, and Farmers' & Merchants' Union Bank, Columbus, Wisconsin. p2-5.